2024 time change dates for United States
At 2:00 AM the clocks jump straight to 3:00 AM in United States. That hour never happens, and everyone loses an hour of sleep.
At 2:00 AM the clocks return to 1:00 AM, so that hour is lived through twice and the night is an hour longer.
Countdown to the next change
Economic Impact of DST in United States
The economic effects of Daylight Saving Time in United States are real but modest, and studies disagree on their size. Retailers and hospitality businesses generally favour DST, arguing that lighter evenings encourage shopping, dining out and other after-work spending — the US retail lobby was one of the main forces behind the 2005 extension of the DST period.
The transitions themselves carry a cost. Research from Chmura Economics has put the one-off economic cost of the spring change in the United States at roughly $430 million a year, driven by lost productivity, workplace injuries and the health effects of a disrupted night's sleep.
Does DST Actually Save Energy?
This was the original justification, and it is the claim that has held up worst. A US Department of Energy report to Congress in 2008 measured the four weeks added to DST in 2007 and found a saving of about 0.5% of daily national electricity use — real, but small.
Other work has found no saving at all. A well-known study of Indiana, which adopted DST statewide in 2006, found residential electricity use actually rose by 1–4%: households used less lighting but more air conditioning on hot summer evenings. Any lighting savings are also partly offset by extra petrol use as people travel more in the lighter evenings.
Background
- Roughly 70 countries use some form of DST, but they are concentrated in Europe and North America. Most of Africa and Asia do not.
- Germany and Austria-Hungary were the first countries to adopt DST nationally, in April 1916, as a wartime fuel-saving measure.
- The Energy Policy Act of 2005 extended US DST by four weeks starting in 2007, moving the start to the second Sunday in March and the end to the first Sunday in November.
Technology and Time Changes in 2024
Phones, computers and anything else that syncs with an internet time server handle the transition on their own. What still catches people out in United States is the long tail of devices that don't: car dashboards, ovens and microwaves, wall clocks, older thermostats, and cheap alarm clocks with a DST setting hard-coded to a schedule that has since changed.
For anyone running servers, the transitions are a recurring source of bugs — duplicated or missing local timestamps around the changeover, cron jobs that fire twice or not at all, and stale operating system timezone databases. Storing timestamps in UTC and keeping the tzdata package current avoids almost all of it.
Agricultural Considerations
The story that DST was introduced for farmers has it exactly backwards. Farmers in United States and elsewhere were among its most persistent opponents, and the American farm lobby successfully campaigned to have national DST repealed after the First World War.
The reason is straightforward: farm work follows the sun, not the clock. Moving the clock forward just means doing the same work an hour earlier by the clock, while deliveries, markets and hired labour all shift with it. Dairy farmers make the point most often, since cows keep to their own schedule and take several days to adjust to a changed milking time.
Tips for United States
Consider the time change when scheduling meetings with people in other time zones.
Use the phrase 'Spring forward, fall back' to remember which direction to change your clocks.
Use the extra evening daylight in summer for outdoor activities and vitamin D.
Remember that not all countries change on the same date - check international meeting times carefully.
Frequently asked questions
When do the clocks change in United States in 2024?
Clocks go forward on Sunday, March 10, 2024 and back on Sunday, November 3, 2024.
Which way do the clocks go?
"Spring forward, fall back" is the usual mnemonic: forward one hour in spring, back one hour in autumn.
Do I have to change anything myself?
Phones, computers and anything that syncs over the internet update on their own. Car clocks, ovens, microwaves and older wall clocks generally do not.
Is Daylight Saving Time being scrapped?
It has been proposed in many places and adopted in few. The European Parliament voted in 2019 to end mandatory clock changes and the change has stalled; in the United States the Sunshine Protection Act has repeatedly passed the Senate without becoming law. Most of the world that changes its clocks is still changing them.